source: vbox/trunk/src/libs/xpcom18a4/python/src/PyISimpleEnumerator.cpp

/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is the Python XPCOM language bindings.
 *
 * The Initial Developer of the Original Code is
 * ActiveState Tool Corp.
 * Portions created by the Initial Developer are Copyright (C) 2000
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Mark Hammond <MarkH@ActiveState.com> (original author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

//
// This code is part of the XPCOM extensions for Python.
//
// Written May 2000 by Mark Hammond.
//
// Based heavily on the Python COM support, which is
// (c) Mark Hammond and Greg Stein.
//
// (c) 2000, ActiveState corp.

#include "PyXPCOM_std.h"
#include <nsISimpleEnumerator.h>

static nsISimpleEnumerator *GetI(PyObject *self) {
        nsIID iid = NS_GET_IID(nsISimpleEnumerator);

        if (!Py_nsISupports::Check(self, iid)) {
                PyErr_SetString(PyExc_TypeError, "This object is not the correct interface");
                return NULL;
        }
        return (nsISimpleEnumerator *)Py_nsISupports::GetI(self);
}


static PyObject *PyHasMoreElements(PyObject *self, PyObject *args)
{
        if (!PyArg_ParseTuple(args, ":HasMoreElements"))
                return NULL;

        nsISimpleEnumerator *pI = GetI(self);
        if (pI==NULL)
                return NULL;

        nsresult r;
        PRBool more;
        Py_BEGIN_ALLOW_THREADS;
        r = pI->HasMoreElements(&more);
        Py_END_ALLOW_THREADS;
        if ( NS_FAILED(r) )
                return PyXPCOM_BuildPyException(r);
        return PyInt_FromLong(more);
}

static PyObject *PyGetNext(PyObject *self, PyObject *args)
{
        PyObject *obIID = NULL;
        if (!PyArg_ParseTuple(args, "|O:GetNext", &obIID))
                return NULL;

        nsIID iid(NS_GET_IID(nsISupports));
        if (obIID != NULL && !Py_nsIID::IIDFromPyObject(obIID, &iid))
                return NULL;
        nsISimpleEnumerator *pI = GetI(self);
        if (pI==NULL)
                return NULL;

        nsISupports *pRet = nsnull;
        nsresult r;
        Py_BEGIN_ALLOW_THREADS;
        r = pI->GetNext(&pRet);
        Py_END_ALLOW_THREADS;
        if ( NS_FAILED(r) )
                return PyXPCOM_BuildPyException(r);
        if (obIID) {
                nsISupports *temp;
                Py_BEGIN_ALLOW_THREADS;
                r = pRet->QueryInterface(iid, (void **)&temp);
                pRet->Release();
                Py_END_ALLOW_THREADS;
                if ( NS_FAILED(r) ) {
                        return PyXPCOM_BuildPyException(r);
                }
                pRet = temp;
        }
        PyObject *ret = Py_nsISupports::PyObjectFromInterface(pRet, iid);
        NS_IF_RELEASE(pRet);
        return ret;
}

// A method added for Python performance if you really need
// it.  Allows you to fetch a block of objects in one
// hit, allowing the loop to remain implemented in C.
static PyObject *PyFetchBlock(PyObject *self, PyObject *args)
{
        PyObject *obIID = NULL;
        int n_wanted;
        int n_fetched = 0;
        if (!PyArg_ParseTuple(args, "i|O:FetchBlock", &n_wanted, &obIID))
                return NULL;

        nsIID iid(NS_GET_IID(nsISupports));
        if (obIID != NULL && !Py_nsIID::IIDFromPyObject(obIID, &iid))
                return NULL;
        nsISimpleEnumerator *pI = GetI(self);
        if (pI==NULL)
                return NULL;

        // We want to fetch with the thread-lock released,
        // but this means we can not append to the PyList
        nsISupports **fetched = new nsISupports*[n_wanted];
        if (fetched==nsnull) {
                PyErr_NoMemory();
                return NULL;
        }
        memset(fetched, 0, sizeof(nsISupports *) * n_wanted);
        nsresult r = NS_OK;
        PRBool more;
        Py_BEGIN_ALLOW_THREADS;
        for (;n_fetched<n_wanted;) {
                r = pI->HasMoreElements(&more);
                if (NS_FAILED(r))
                        break; // this _is_ an error!
                if (!more)
                        break; // Normal enum end.
                nsISupports *pNew;
                r = pI->GetNext(&pNew);
                if (NS_FAILED(r)) // IS an error
                        break;
                if (obIID) {
                        nsISupports *temp;
                        r = pNew->QueryInterface(iid, (void **)&temp);
                        pNew->Release();
                        if ( NS_FAILED(r) ) {
                                break;
                        }
                        pNew = temp;
                }
                fetched[n_fetched] = pNew;
                n_fetched++;
        }
        Py_END_ALLOW_THREADS;
        PyObject *ret;
        if (NS_SUCCEEDED(r)) {
                ret = PyList_New(n_fetched);
                if (ret)
                        for (int i=0;i<n_fetched;i++) {
                                PyObject *new_ob = Py_nsISupports::PyObjectFromInterface(fetched[i], iid);
                                NS_IF_RELEASE(fetched[i]);
                                PyList_SET_ITEM(ret, i, new_ob);
                        }
        } else
                ret = PyXPCOM_BuildPyException(r);

        if ( ret == NULL ) {
                // Free the objects we consumed.
                for (int i=0;i<n_fetched;i++)
                        fetched[i]->Release();

        }
        delete [] fetched;
        return ret;
}


struct PyMethodDef 
PyMethods_ISimpleEnumerator[] =
{
        { "HasMoreElements", PyHasMoreElements, 1},
        { "hasMoreElements", PyHasMoreElements, 1},
        { "GetNext", PyGetNext, 1},
        { "getNext", PyGetNext, 1},
        { "FetchBlock", PyFetchBlock, 1},
        { "fetchBlock", PyFetchBlock, 1},
        {NULL}
};